ZHCSHW5A September   2017  – December 2017 TPS23521

PRODUCTION DATA.  

  1. 1 特性
  2. 2 应用
  3. 3 说明
    1.     Device Images
      1.      简化原理图
  4. 4 修订历史记录
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Switching Characteristics
    7. 6.7 Typical Characteristics
  7. 7 Parameter Measurement Information
    1. 7.1 Relationship between Sense Voltage, Gate Current, and Timer
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Current Limit
        1. 8.3.1.1 Programming the CL Switch-Over Threshold
        2. 8.3.1.2 Setting Up the PROG Pin
        3. 8.3.1.3 Programming CL1
        4. 8.3.1.4 Programming CL2
      2. 8.3.2 Soft Start Disconnect
      3. 8.3.3 Timer
      4. 8.3.4 Gate 2
    4. 8.4 Device Functional Modes
      1. 8.4.1 OFF State
      2. 8.4.2 Insertion Delay State
      3. 8.4.3 Start-up State
      4. 8.4.4 Normal Operation State
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Selecting RSNS
        2. 9.2.2.2 Selecting Soft Start Setting: CSS and CSS,VEE
        3. 9.2.2.3 Selecting VDS Switch Over Threshold
        4. 9.2.2.4 Timer Selection
        5. 9.2.2.5 MOSFET Selection and SOA Checks
        6. 9.2.2.6 EMI Filter Consideration
        7. 9.2.2.7 Under Voltage and Over Voltage Settings
        8. 9.2.2.8 Choosing RVCC and CVCC
        9. 9.2.2.9 Power Good Interface to Downstream DC/DC
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12器件和文档支持
    1. 12.1 器件支持
      1. 12.1.1 第三方产品免责声明
    2. 12.2 文档支持
      1. 12.2.1 相关文档
    3. 12.3 接收文档更新通知
    4. 12.4 社区资源
    5. 12.5 商标
    6. 12.6 静电放电警告
    7. 12.7 Glossary
  13. 13机械、封装和可订购信息

封装选项

机械数据 (封装 | 引脚)
散热焊盘机械数据 (封装 | 引脚)
订购信息

9.2.2.7 Under Voltage and Over Voltage Settings

Both the threshold and hysteresis can be programmed for under voltage and over voltage protection. In general the rising UV threshold should be set sufficiently below the minimum input voltage and the falling OV threshold should be set sufficiently above the maximum input voltage to account for tolerances. For this example a rising UV threshold of 35 V and a falling UV threshold of 33 V was chosen as the target. First, choose RUV1 based on the 2 V UV hysteresis as shown below.

Equation 25. TPS23521 tps23523_equation24.gif

Once RUV1 is known RUV2 can be computed based on the target rising UV threshold as shown below.

Equation 26. TPS23521 tps23521_equation14.gif

The OV setting can be programmed in a similar fashion as shown in equations below.

Equation 27. TPS23521 tps23521_equation15.gif
Equation 28. TPS23521 tps23521_equation16.gif

Optional filtering capacitors can be added to the UV and OV to improve immunity to noise and transients on the input bus. These should be tuned based on system requirements and input inductance. In this example place holders were added to the PCB, but the components were not populated.